Koo Seo Jin reaches an all-time low when he uses his power as a theme park director to decommission Wonderland’s popular circus. Refusing to give into the demands of her frosty boss, ringleader Jang Ha Na puts up a fight, but is thrown off guard when Seo Jin’s secret persona reveals itself with genuine kindness. In the battle to save her circus, Ha Na realizes she must tease out Seo Jin’s brighter side with magic, wonder and love, but who’s listening — Jekyll or Hyde?

Hyo-joo, an untenured instructor at a boys’ high school is assigned to a class of seniors as a HR teacher. She notices that a specialized dance student Jae-ha is absent from the self-study session, and finds him practicing refined dance movements in the gym. The next day Hae-young, the school board chairman’s daughter arrives as a tenured instructor, which was the position assumed to be offered to Hyo-joo soon. Hae-young, sweet and having grown up with no worries, treats Hyo-joo with affection, but Hyo-joo only gives her the cold shoulder. Then one day, Hyo-joo witnesses Hae-young and Jae-ha in the gym, having sex, and from that moment on, she starts feeling an inexplicable sense of humiliation towards Hae-young while gradually falling under the influence of Jae-ha’s elusive charm.